Friday, April 22, 2011

Complexity and Cognition

You might think that complex systems are complicated, but they often aren't.

That may be a bit too cutesy, but it does make a nice distinction between complexity and complication in network systems. Modern jet fighter planes and computer circuit boards are complicated structures – they are composed of millions of parts arranged in intricate ways for a myriad of purposes – but they are not complex. Why? Because they don't change, and if they do change, then that change usually breaks them. They are rather rigid structures, with regular, predictable, and reliable interactions among their parts. After all, you don't want a jet fighter that suddenly decides to start behaving differently in a dog fight.

On the other hand, complex structures such as the human body change constantly, acquiring new cells, functions, and capabilities and discarding old ones. They are dynamic, and not just in the sense of moving parts. They are dynamic in the ways the parts within the structure interact with each other and in the ways all those structural parts interact with the ecosystem that encloses them. And the trigger for this dynamism is sometimes quite simple. In Networks of the Brain, Sporns paraphrases Herbert Simon to say:

First … most complex systems can be decomposed into components and interactions possibly on several hierarchical levels. Second, complexity is a mixture of order and disorder, or regularity and randomness, which together account for the nontrivial, nonrepeating nature of complex structures and their diverse dynamics. (279)

Brains, then, owe their neural complexity to "the union or coexistence of segregation and integration expressed in the multiscale dynamics of brain networks" (278), to the mix and tension of "some degree of randomness and disorganized behavior with some degree of order and regularity" (281,282), and to "rich and dynamic contextual influences" (286). This dynamic complexity in the brain is what gives rise to the emergent property of consciousness, or as Sporns says it, "Consciousness emerges from complex brain networks as the outcome of a special kind of neural dynamics" (298).

nodes and clusters of nodes – from single neurons to social networks and natural ecosystems – that are able to form meaningful patterns within any given scale and across all scales (segregation and integration of functions)

a fluid tension between regularity and randomness, order and chaos, as patterns form, fade, and reform across the web of nodes as nodes form their own patterns and then harmonize those patterns with the other patterns forming, fading, and reforming elsewhere in the neural network

I need a better picture, so I'll call again on the image of the brain as two musical groups: a left hemisphere orchestra and a right hemisphere jam band. Imagine the New York Philharmonic meets The Allman Brothers Band on the same circular, floating stage: the Philharmonic stage left, the Brothers stage right. The musicians can hear both each other and the speakers that circle the stage, filtering and focusing the sound from two omnidirectional microphones pointed out toward the world. (The musicians can also see, feel, smell, and taste, but let's not overcomplicate this metaphor. Sound will suffice, I think). Finally, they have microphones on stage through which they can play, or not, their sounds to the outside world.

Both bands are mature. They know their chops, their instruments, and each other. They know how to make music on their instruments and how to blend their individual music into the music being made by the other instruments on the stage AND to the music coming in over the speakers from the outside world. When they are all rested and focused, then they can make wonderful sounds that harmonize internally with the other sounds on the stage and externally with the sounds coming over the speakers from outside. When they are not rested or they've had too much to drink, then they make silly, discordant sounds, sometimes truly awful sounds.

Because they are mature musicians, they are dedicated to learning more about their instruments, each other, and their music, so much of the time they are focused on their internal, on-stage noodling, trying this new combination of instruments, this new musical motif or riff, or practicing and honing old motifs and riffs to have ready at hand when they need them. They have a huge repertoire of different sounds that they can call upon at an instance, and they know which among them can make which sounds. None of them can make all sounds, and some of them can make only a few sounds, but they all know how to group and regroup themselves as needed. Sometimes they group as strings, which will pull together the violins and guitars, sometimes as low register instruments, which pulls together the tubas and bass guitars. The point is that they have a rich repertoire of established sounds, and they are constantly working to add to that repertoire.

But they are also keenly aware of the sounds coming from outside, and they will respond to sounds they hear. They can faithfully reproduce and harmonize with sounds that they know and other bands with which they've played before, creating a pleasing musical interlude, melodies and movements arcing back and forth between the different bands both on a single stage and across the different stages.

This is where it gets fun. If you are lead guitarist Duane Allman (an individual neuron in the right hemisphere of the brain), then you are listening to your bandmates Dicky Betts, Gregg Allman, Butch Trucks, Jai Johnny Johnson, and Berry Oakley AND to the New York Philharmonic just across the stage with tonight's guest cellist Yo Yo Ma AND to the sounds coming from the other orchestra/jam band made up of the Boston Pops and the Grateful Dead. You are listening for a place for you to fit in. You at last hear a space for you and you make your sound. It's a particularly pleasing, clever riff, so Yo Yo Ma echoes it. You echo back. It's picked up by Phil Lesh of the Dead, reworked slightly, and comes back to you again. You restate it, then rework it again, expanding it by a few bars. The woodwinds in both orchestras join in, and the musical pattern soars. Everybody's happy. Everybody understands the same thing. The band has created a pattern of sound that you, Duane Allman, could not have produced alone but that could not have been produced without you.

Or perhaps you make an awkward sound, something that just doesn't work in the current flow. The musical pattern becomes chaotic for a moment until the other musicians ignore you. The music rights itself, and the bands move on as Brother Gregg leans over and whispers to you, "We're playing in G, dude."

Why did Gregg do this for you? Because – and this is the most important point – there is no conductor, no central processing unit, no boss. The musicians (the individual neurons) are all on their own, seeking a way to integrate their individually produced contributions into the whole. They are each guided by their own, unique abilities to produce unique sounds and by a shared interest in harmonizing, synchronizing, and otherwise fitting their sounds into all the other sounds to create a pleasing, workable whole.

In resourceful, well-tuned bands (brains), each musician finds a way to fit into the whole, most of the time playing a supporting, complementary role, sometimes taking the lead, but always looking to add her own unique sound to the group and its music. In damaged or deranged bands, the musicians are stuck playing the same tune over and over, or they cannot integrate with each other so that no coherent music emerges from their individual sounds.

If I understand Sporns, this is how cognition takes place: emerging, dynamic patterns of firings of individual nodes that group, fall apart, regroup in clusters across the left and right hemispheres of an individual brain AND across different brains, mediated by our actions and symbol systems.

So what does this view of cognition mean? Well, for me as an English teacher, it means that if I want to understand fully the meaning of Shelley's poem Ozymandias then I must be mindful of the complex interactions within Shelley's mind, the complex interactions of the symbol system he used to compose the poem (English language, poetry, sonnet, etc.), the complex interactions of Shelley with his ecosystem (natural, social, intellectual, etc.), the complex interactions of the poem with its ecosystem (production printing, distribution, consumption, etc.), the complex interactions of Shelley's readers with the poem and with each other, the complex interactions of all those interactions with me, and the complex interactions within my own mind.

This effectively describes an approximately infinite number of dynamic interactions that I must master in order to understand completely one fourteen-line poem, and it's why we can write about one poem for two hundred years and still not exhaust it. Basically, what it shows is that we can form a richer understanding of Ozymandias, but we cannot form a complete understanding. This is a crisis for students confronted with a regime of objective tests. In the face of this crisis, students do the only sensible thing: they either demand to know the correct answer, or they walk away. We force them to choose either to play the one correct tune over and over or to degenerate into chaos. Let us hope they are able to choose wisely.